Method of applying a protective closure to a threaded opening



Dec. 10, 1963 H. c. OAKES, JR 3,113,377

METHOD OF APPLYING A PROTECTIVE CLOSURE TO A THREADED OPENING Filed Feb. 21, 1958 5 Sheets-Sheet 1 INVENTOR.

Dec. 10, 1963 H, c. CAKES, JR 3,113,377

METHOD OF APPLYING A PROTECTIVE CLOSURE TO A THREADED OPENING 5 Sheets-Sheet 2 Filed. Feb. 21, 1958 INVENTOR.

BY Far/7y C 0256;? @77 M M dfiorneys.

Dec. 10, 1963 H. c. OAKES, JR 7 METHOD OF APPLYING A PROTECTIVE CLOSURE TO A THREADED OPENING 5 Shets-Sheet 3 Filed Feb. 21, 1958 INVENTOR.

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Dec. 10, 1963 H. c. CAKES, JR 3,113,377 7 METHOD 0 APPLYING A PROTECTIVE CLOSURE To A THREADED OPENING Filed Feb. 21, 1958 s Sheets-Sheet 4 129 1g? 202w? AV /V I N #75; 128 Ill! 1 /-767 137 i 167 I 777 172 92 I 140 147 166 I 162 INVENTOR. Fa if 3277;; C @zZw/Z BY M Z dfiorveys- Dec. 10, 1963 H. c. CAKES, JR ,3 7

METHOD OF APPLYING A PROTECTIVE CLOSURE TO A THREADED OPENING Filed Feb. 21, 1958 5 Sheets-Sheet 5 fmM/M 0/5 FEED 15! IN VENTOR.

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United States Patent 3,113,377 METHGD @l APPLYENG A PRGTECTFVE CM)- SiJRE TO A THREADED OPENING Harry C. flakes, .llr., Buifalo, N.Y. (34 5. Academy St., PO. Box 331, Wyoming, N31.) Filed Feb. 21, 1958, Sea. No. 716,704 2 (llaims. (Cl. 29-523) This invention relates to a method of applying a protective closure to a threaded opening.

ln the manufacture of certain mechanical devices, and particularly sub-assemblies, it is often desirable or necessary to temporarily close threaded openings to prevent foreign matter from entering the device when the latter is shipped or otherwise handled prior to assembly. Various means have been proposed and utilized for providing such a protective closure, with varying degrees of satisfaction and success. However, the main criticisms of most of such means are that they are too expensive, or complicated, to be commercially attractive for high volume application.

The concept of the present invention resides in the provision of a temporary protective closure for threaded openings, which is of low cost, and which is commercially attractive, especially for high volume application. Briefly, the invention concerns the use of a cup-like element made from a thin, malleable material, which element is preformed to enter a threaded opening, and is expanded when in said opening, to conform to the thread shape. in 811011 manner, the insert is securely locked within the threaded opening to effectively prevent entry of foreign matter into the opening, and may be easily removed from the opening when desired, as when screwing a threaded member into the opening.

The main object of this invention is to provide a method of applying a protective closure to a threaded opening.

A further object is to provide a method of applying a protective closure to a threaded opening which closure may be conveniently applied to the opening, will prevent entry of foreign matter into the opening, and which may be easily removed from the opening.

Still another object of this invention is to provide a method of applying a protective closure to a threaded opening, which closure is of low material and application cost so as to be commercially attractive, especially for high volume application.

A further object is to provide means for either manual or automatic application of a protective closure to a threaded opening.

These and further objects and features of the invention will become more apparent from the following description and accompanying drawings wherein:

FIG. 1 is a perspective view of a tool assembly which may be used for the manual practice of the method of the invention;

2 is an enlarged section View through one of the tools shown in FIG. 1;

Fl 3 is a fragmentary view of the tool assembly of H6. 1, showing an initial step in the method;

PEG. 4 is the sa 1e but showing the position of the tool assembly after formation of a cup-shaped member;

H6. 5 is the same but showing the arrangement of the cup-shaped member prior to insertion in a threaded opening;

PEG. 6 is the same but showing the cup-shaped member after positioning in a threaded opening;

H6. 7 is the same but showing the cup-shaped member after being expanded within the threaded opening;

FlG. 8 is a perspective view of a closure arrangement formed by the method of the invention;

MG. 9 is a side view of a machine which may be used for automatically practicing the method of the invention;

REG. 10 is a section view as seen from line in PEG. ll is the same as PK 9 but showing the relative position of certain parts during one phase of operation;

HS. 12 is a section view as seen from line 12-412 in FIG. 11;

FIG. 13 is a fragmentary view of the machine of FIG. 9 but as seen from the other side;

FIG. 14 is a section view as seen from line 14-14 in FIG. 9;

HQ. 15 is a section view as seen FIG. 9;

FIG. 16 is a fragmentary view of a forming mandrel (enlarged) used the machine of FlG. 9, and showing a protective closure on the mandrel end ready for insertion into a threaded opening;

17 is the same but showing the mandrel end and protective closure after insertion into a threaded opening;

FIG. 18 is the same but showing the condition of the protective closure after a forming operation is rendered thereupon;

FIG. 19 is the same but showing the forming mandrel withdrawn from the threaded opening and a formed protective closure in position within the ope ring;

PEG. 20 is a graph illustr ng the rcladve operating phases of various cam wheels used in the machine of PEG. 9; and

FIG. 21 is a schematic diagram showing the electrical connections between certain electrical components used in the machine of FIG. 9.

The method of the invention may be produced either manually, i.e., with the use of hand held tools, or by the use of automatic machinery, both means being fully disclosed herein.

from line 15-15 in Manual M eci'zunism Referring to the drawings, PlGS. 1 to 8 inclusive illustrate a manual means for practicing the method of the invention, which means consist of a forming mandrel 51 and a die piece 52. The mandrel 51 includes a heavy walled cylindrical member :53, having an axially arranged bore 54, a plunger 55 slidably arranged in the bore, and a lever or handle as loosely fitted to the upper end of the plunger between a pair of nuts 57. The member 53 has a head or re. ed portion 58 on its upper end, which serves as a fulcrum point for the lever 56.

It will be seen that by moving or squeezing the handle 56 toward the cylinder 53, the plunger 55 will be moved upwardly in the cylinder. The plunger 55 has an integral round head portion 59 at the lower end, while a rubber cylinder is arranged on the plunger between the head 59 and the bottom surface of the cylinder 53. Upward movement of the plunger 55, will compress the rubber cylinder at, so that its side walls will bulge outwardly. A spring 62 is compressively arranged about the plunger 55 between a shoulder 63 on the plunger and a circumferential shoulder as of the cylinder which slidingly guides the plunger.

The die piece 52 has a central bore 65, which is of slightly greater diameter than that of the plunger head portion 59 and rubber cylinder 61. Actually, this difference in diameters is such as to allow clearance for pushing a metal foil 67 into the bore 66. The metal foil, which is preferably made from aluminum, has been found most satisfactory when it is approximately two-thousandths of an inch thick.

In practicing the method of the invention with the manually operable means above described, a piece of metal foil 6'7 is placed atop the die piece 52 (FIG. 3), and the head 59 and rubber cylinder 61 of the forming mandrel -1, are moved down into the bore 66 to form the foil into a cup-shaped element 71 (FIG. 4). The mandrel 51 is then moved upwardly to pull the head 59, rubber cylinder 61 and the cup-shaped element '71 from the bore 66, the element 71 staying on the lower end of the mandrel because the coefiicient of friction of the rubber cylinder 61 is greater than that of the die bore 66 (FIG. 5). Next, the cup-shaped element 71, and lower end of mandrel 51, are inserted into a threaded opening 72 (FIG. 6). The plunger 5-5 and plunger head 59 are moved upwardly, by squeezing action on the handle 56, causing the rubber cylinder 61 to be compressed and expand outwardly, thus forcing the side walls of the cupshaped element 71 into conformity with the threads of the opening (FIG. 7). Pressure on the handle 56 is released, permitting the rubber cylinder 61 to assume normal shape, and simultaneously, the mandrel 51 is moved upwardly to free the end thereof, i.e., rubber cylinder 61 and plunger head 59, from engagement with the cupshaped element '71. The distorted cup-shaped element 71 will now remain in the threaded opening (FIG. 8) since it is held by the threads thereof. The resulting enclosure will protect the threaded opening against entry of foreign matter, and will remain in such protective condition until the element 71 is purposely removed at a later time.

Automatic Mechanism Referring now more particularly to FIGS. 9 to of the drawings, a machine for automatically practicing the method of the invention includes a vertically arranged forming mandrel or plunger assembly 96, the lower end of which projects through an opening 91, formed in the bottom of a housing or enclosure 92, when the machine is in condition for commencement of a full operating cycle.

The plunger assembly 90, which is more clearly seen in FIG. 14, includes a centrally arranged rod 93 supported for axial movement within a tube or sleeve 94 which is slidably supported within a pair of spaced busl1- ings 96. The bushings 96 are located in a bore 97 formed in a block 98 which is rigidly secured at one side to a rear wall 99 of the housing 92. The lower end of the rod 93 has a reduced diameter portion 101, a part of which is slidably arranged in a cap 102 threadably secured to the lower end of the sleeve 94. The reduced diameter portion 101 projects beyond the bottom of the cap 102 and has an enlarged head 103- adapted to support a resilient cylindrical member 104, between the head 163 and the bottom of the cap 192. The resilient member is preferably made of rubber, and has an internal diameter equal to that of the portion 101 and a normal external diameter equal to that of the enlarged head 163. It will be seen that upward movement of the rod 93 will cause movement of the enlarged head 193 toward the bottom of the cap 102, whereby the rubber cylinder 194 will be compressed and the sides thereof caused to bulge radially'outward, i.e., the external diameter thereof will be increased while the axial length will be decreased.

The upper end of the sleeve 94 passes through and is affixed to a generally cubic block 1% having a groove or slot 197, extending horizontally in the block and opening upon one side thereof. On the side of the block 1&6 opposite to that on which the groove 197 opens, is rigidly secured a rectangular arm 198 which extends upwardly from the block so as to be generally parallel with the axis of the rod 93. A rod actuating means, preferably in the form of a solenoid 199, is affixed to a side of the arm 108, in such manner that an armature or plunger 111 of the solenoid is in axial alignment with, and may be connected to the upper end of the rod 93 by a pin means 112. Upon actuation of the solenoid 109 the rod 93 will be moved upwardly to compress the rubber cylinder 104 and cause bulging thereof, as heretofore explained.

The extreme upper end of the arm 108 is beveled to provide a cam surface 113, which is tapered downwardly from the side of the arm on which the solenoid 199 is secured. The cam surface 113' is adapted to engage a roller 114 mounted upon the end of a plunger 116 forming part of a normally open electrical switch 117, the latter being maintained in fixed position by bracket means (not shown) which may be rigidly secured to the rear wall 99 of the housing 92. Upward movement of the arm 1% will cause the cam surface 113 to urge the plunger 116 inwardly to close the switch 117, and complete an electrical circuit for machine operational purposes, as will be presently described. It will be noted that the switch 117 will be held in closed condition as long as engagement of the roller 114 with the back surface of the arm 198 is maintained.

A second normally open electrical switch 118, is secured to the side of the arm 1% and has an operating plunger 119, which may be moved by a threaded finger 12% held in axial adjustment by a nut 121 toward one end of an arm 122. The other end of the arm 122 is arranged to straddle the rod 93 and is held in abutment against a shoulder 123 of the rod 93, by a nut 124-. Movement of the rod 93 axially in an upward direction will cause engagement between the finger 129 and the plunger 119, and eventual closure of the switch contacts to complete an electrical circuit for machine opeartional purposes, as will be presently described.

It is to be noted that operation of the switch 117 is caused by movement of the arm 198, while operation of the switch 118 is caused by movement of the rod 93.

Projecting from the side of the block 106 is a stub shaft 126 which is arranged to engage, during a certain time in the upward movement of block 196, one end of a rocker lever 127 pivotally mounted upon the rear wall 99 of the housing 92. The other end of the rocker lever 127 is pivotally connected to a rod 128 which extends downwardly and is pivotally connected to the end of a crank arm 129. The crank arm 129, is connected via a one-way clutch (not shown), to a wheel 131 which has a pair of radially directed flanges 132 each one of which is arranged at a peripheral edge of the wheel, to form a groove 133 on the circumference of the wheel. The groove 133 is adapted to receive a strip of metal foil 134 from a reel 136, which is rotatably supported by a shaft 137 affixed to the rear wall 99, and to press the foil against a guide block 138 whereby the foil may be urged in the direction of a cutting mechanism 139. It will be noted that the wheel flanges 132 straddle the contact portion of the guide block 138. A bifurcated lever 140, pivotally mounted upon a pin 141 supported by a block 142 which is affixed to a base'plate 143, is arranged to positionally hold the Wheel 1131. 144, arranged near the end of the lever 141B, engages one end of a spring 146 compressively positioned between the end of the screw 144 and the base plate 143. In such manner the pressure of the wheel 131 upon the metal foil being used may be adjusted to provide the necessary frictional engagement to move the foil when the wheel 131 is rotated.

A spring 14-7 interconnects the upper end of the rod 128 to a pin 1 48 affixed to the rear wall 99, which spring serves to pull the rod upwardly when the stub shaft 126 is moving out of engagement with the end of the rocker lever 127 The wheel .131 will be rotated to advance the metal foil 134 only during downward movement of the rod 128; upon upward movement of the rod, the one-way clutch (not shown) of the wheel arrangement will allow pivotal movement of the crank arm 129 without rotary movement of the wheel 131. V

The cutting mechanism 139 includes: a lever 151 which is pivotally aifixed at one end by a bolt 152 to an upwardly projecting boss or lug portion 153 of the guide block 138; a cutting blade 154 affixed to the side of the lever 151 with the cutting edge of the blade arranged in scissorlike engagement with a forward edge of the guide block An adjusting screw 138; and a rod 156 pivotally affixed to the other end of the lever 151. A torsion spring 157, secured to the bolt 1-52, is arranged to constantly urge the lever 151 so that the cutting blade 154 will move downwardly to effect a foil cutting operation when a part of the foil strip is under the blade.

The rod 156 is pivotally connected at its upper end to an offset rocker lever or arm 153, which is rotatably mounted near its mid-portion upon a stub shalt 159 affixed to the side of the block 98. The other end of the rocker arm 158 has a roller 161 afllxed at the side, which is in rolling contact with the profile or periphery of a cam element 162, rigidly secured to a rotatable shaft 163. The torsion spring 157, acting upon the roller 161 through the lever 151, rod 155, and arm 158, is of sulficient strength so as to maintain the roller 161 in rolling contact with the profile of the cam element 162 at all times. The cam profile is such as to allow or provide the necessary reciprocating movement of the rocker arm 158 and attached elements, so as to provide a foil cutting operation [at the proper time in the operating cycle of the machine, as will be more clearly explained hereinafter.

A bell crank 164, which is rotatably mounted upon a bolt 16% affixed to a block 167 secured to the rear wall 99, has a bifurcated end providing parallel arms 168, each of which has a roller 16% mounted on the inner side for engagement with groove N7 of the block 106. Supported upon one side of the bell crank 164 between the fulcrum and the bifurcated end, is a roller .171 maintained in rolling contact with the profile or periphery of a cam 17 2, which is rigidly secured to the rotatable shaft 163. The other arm of the bell crank 164- has a pin 173 to which is secured the end of a spring 174, the other end of the spring being secured to a pin 176 aflixed to the side of a strap 1'77.

'llhe strap has a pair of slightly elongated holes 178 at each end which allow shifting movement of the strap upon supporting bolts 179 which are athxed to blocks 181 secured to the rear wall 99 of the housing 92. A spring 182, is arranged with one end secured to the pin 176 and the other end to a pin 183 afiixed to one of the blocks 181. While both springs 174 and 182 are normally under tension, the former spring is heavier and stronger than the latter. A limit pin 184 projects from the side of the strap 177 and is arranged to be engaged by the end of the arm of the bell crank 164, as best illustrated in FIG. 9.

From the foregoing it will be seen that as the cam 172 is caused to rotate, the profile thereof acting through the roller 171, will cause a pivotal movement of the rocker arm 164 about the fulcrum pin 166, resulting in the reciprocal movement of the block 196, by reason of engagement of the rollers 1d9 therewith. Such movement of the block 106 will result in vertical movement of the plunger assembly 90 and the arm 108 with its attached parts. The profile of cam 172 is designed to provide the desired rate and period of movement of these parts, as required in the operating cycle of the machine, all of which will be presently explained.

It will be noted that the spring 174 serves to urge the roller 171 into engagement with the profile of cam 172 at all times, however, an upward force applied to the lower end of the plunger assembly 93, will lift the roller out of contact with the cam profile. Such upward movement of the plunger assembly will result in a slight pivotal movement of the bell crank 16d and a longitudinal shifting of the strap 177 against the tension of the spring 182. The purpose of providing such a movement of the bell crank 164 by a force applied upwardly against the plunger assembly 93!, is to effect a vertical shifting of the arm 16% to cause operation of the switch 117, for initiating an operating cycle of the machine.

A pair of arms 1% is pivotally mounted at one end by bolts 187 for sliding movement against the lower surface of the base plate 14-3, in the region defined by said plate and the inside of the bottom of the enclosure 92. Each arm has a bolt 18% arranged toward the other end which is adapted to move in a curved guide opening 189 formed in the base plate 143. Each arm 186 is further arranged to have a roller U1 mounted on the upper surface, which rollers project into an opening 192 formed in the base plate 143. A spring 193, is arranged to interconnect the arms 186 and to constantly urge the arms together. Near the end of each arm 186, opposite the pivoted end, is arranged a semicircular bore 1% extending downwardly from the top surface a given distance which together provide a circular die or recess (FIG. 12) adapted to receive the plunger head 1133 and rubber cylinder 164, when the arms are in engagement along their inner sides. The diameter of the die so formed must be slightly larger than that of the plunger head and rubber cylinder, while the depth thereof must be slightly greater than the distance between the bottom surface of the plunger head .103 and the bottom surface of the cap 1192. The die so formed will permit a cup-like closure element to be made when metal foil is forced into the die by the plunger head and rubber cylinder.

lever 1% having a symmetrical wedge-like edge 197 at the lower side extremity, is pivotally mounted upon a shaft 198 secured to the back wall 99. The upper end of the lever 1% has a roller 199 which is held in rolling contact with the profile or periphery of a cam 2491, which is rigidly secured to the shaft 163. The wedge-like edge 1%7 is arranged to act upon the rollers 191 and force the arms 186 apart, when the lower end of the lever 1% is rotated the direction of the rollers, by action of the earn 2% on the upper end of the lever. The profile of cam 2G1 is designed to provide the desired action of the arms 1% as required in the operating cycle of the machine.

A spur gear 292 is rigidly secured to the shaft 153, and is engaged by a rack 2'33 which is connected at the upper end to a piston rod 284. The latter is connected to a piston head 286 (FIG. 21) slidably arranged for recipro' cable motion within a cylinder 2%, which may be moved by pressure fluid, i.e., pneumatic or hydraulic, alternately admitted via pipes 2d? and 2%, to opposite ends of the cylinder by a slide valve assembly 213"), including a solenoid 219. Both the cylinder 2.86 and ymve 269 are connected to the back Wall 91 by bracket means (not shown). The stroke of the piston 2%, is regulated to provide a movement of the shaft 163 as the rack 2133 is moved downwardly, and a 180 reverse movement as the rack is moved upwardly. A roller or flanged wheel 211 is arranged for engagement with the side of the rack opposite the toothed side, to maintain the teeth of the rack in engagement with the spur gear 2%)2.

An arm 2 12 afiixed to the piston rod 2%, has an axially adiustab-le finger 213 arranged for engaging a plunger 21d of a normally open electrical switch 216, which is positionally maintained by bracket means (not shown) affixed to the rear wall )9 of the housing 92. The finger 213 contacts the switch plunger 21d, toward the end of upward movement of the piston rod 264-, to complete an electrical circuit for operating the solenoid 21d of the valve 239, to shift the slide valve and effect reverse movement of the piston 2115.

The operating cycle of the machine, and the coordinated function of the various components will now be described. Assume that the machine is in non-operative condition as illustrated in PEG. 9, and that a cup-shaped closure element 221 (FIG. 16) made from metal foil, is on the lower end of the plunger assembly 9%. The manner in which the closure element 221 is formed and positioned on the end of the plunger assembly will soon be apparent. The machine operator will place a workpiece 222, having a threaded opening 223 to be enclosed by the closure element 221, into engagement with the bottom surface of the cap 132 so that the closure element and the end of the plunger assembly 2-9 are within the threaded opening (FIG. 17). Upward pressure exerted by the operator via the workpiece 22 2 against the cap 102, will cause upward movement of the plunger assembly and arm 1% to close the contacts of switch 117, as has been described. The solenoid 1119 will be actuated by operation of the switch 117 thereby drawing the rod 93 upward relative the sleeve 94, and causing a radial outward bulging of the cylindrical rubber element 1114, to press or force the sides of the closure element 221 into conformity with threads of the opening 223 (FIG. 18). Upward movement of the rod 93 a given distance, will cause closing of the contacts of switch 118 by engagement of the plunger 119 thereof with the finger 12d. Operation of switch 118 will actuate a relay 226 (FIG. 21) which results in the breaking of the electrical circuit to solenoid 1d), and the making of a circuit through solenoid 211), of the valve 269, and reversing the application of pressure fluid to the piston 2415. Upward movement of the rack 203 will result, thus causing rotation of the shaft 163. Cams 162, 172, and 2411 will thus be rotated counter-clockwise (as viewed in PEG. 9), and the bell crank 164' will be rotated to cause upward movement of the plunger assembly 90 and block 166.

After the lower end of the plunger assembly 91} clears the top surface of the arms 186, the cam 201 will rotate lever 197 so that the arms will close (FIG. 12), to provide the circular die =194. Continuing upward movement of the block 106 will cause engagement of the shaft 126 with the end of the lever 127, and the rotation thereof, resulting in the downward movement of the rod 123 Such downward movement of rod 128 will cause rotation of the wheel 131 and the feeding of a given amount of metal foil 134 atop the arms 1% and above the circular die 124. The earn 172 is designed to prevent further lifting of the bell crank 164 after the metal foil is thus positioned over the die 194. Subsequently, the cam 162 will cause movement of the rocker lever 158 so that the rod 156 will move downward and cause the cutting blade .154 to begin shearing or out off of the metal foil.

As the piston rod 2494 moves upwardly the plunger 214 "of switch 216 is moved by the finger 213 (FIG. 11), whereupon the contacts of the switch are closed to complete a circuit through a relay 227. Operation of relay 227, results in establishment of electrical circuits including the breaking of electrical circuit in solenoid 210 of the valve assembly 209, whereupon a spring 223 will move the valve thereof to cause flow of pressure fluid to the cylinder 2% to move the piston 295 and rack 293 downwardly. The extent of counter-clockwise movement of the shaft 163 from beginning to end will be approximately 180.

Such downward movement of rack 164, causes the clockwise movement of the shaft 163- and afiixed cams 16 2, 172 and 2131, and results in the pivotal movement of the bell crank 164- and the downward movement of the plunger assembly 91) and block 1%, until the end of the plunger assembly enters the die 194 and forces the metal foil downwardly therein to form a cup-shaped closure element 221. Downward movement of the plunger assembly 91 is stopped when the bottom surface of the cap 102,

seats upon the upper surface of the arms 136. Rotary motion of cam 291 then causes movement of the lever 1% so that the wedge portion 197 thereof acts upon the rollers 191 to force the arms 1% apart (FIG. When the die end of the arms 186 are moved apart a sutficient distance to provide clearance for the plunger assembly sleeve 94, downward movement of the plunger assembly will resume and continue until it arrives at the initial position, i.e., the end thereof projecting a given distance below the bottom of the enclosure 92. At this point, the cam surface 113 will allow the switch plunger 116 to move outwardly and open the contacts of switch 117, whereupon the machine will be returned to non-operative condition and in readiness for another operating cycle, with a preformed closure element frictionally held upon the lower end of the plunger assembly.

Further understanding of the operating cycle of the various components of the machine, may be gained from a study of the graph shown in FIG. 20. The abscissa represents the counterclockwise motion of the shaft 163 (as viewed in PEG. 9) from 0 to of rotation, and the clockwise motion thereof from 180 to 0, while along the ordinate are certain identified components of the machine. The shaded areas opposite the various components, represent periods of movement or actuation thereof, while the length of such areas correspond to the arcuate distance traversed by the shaft 163, during such movement. The graph clearly shows the relative action, or periods of operation, between the various components, and provides sufficient data so that anyone skilled in the art may design the contours or profiles of cams 162, 172 and 261 to provide the required related action of said components.

The electrical circuit illustrated in FIG. 21 shows how various electrical com onents of the machine are interconnected to be efective in producing the operating cycle of the machine. Certain parts such as switches 117, 118 and 216, as well as certain mechanical elements shown therein, have already been described, hence further discussion of structural detail need not be given thereupon at this time. However, relays 226 and 227 are somewhat non-conventional, hence, further explanation thereupon will not be given.

Relay226 includes a coil 231, an armature or electric conducting bar 232, and two groups of contacts, one of which includes contact points 233 and 234- arranged for simultaneous contact by the armature 232, the other of which includes contact points 236, 237 and 238, arranged for simultaneous contact by the armature 232. The armature 232 is biased, or resiliently loaded, for normal engagement of the contacts of the first group, i.e., contacts 233 and 234, when the coil 231 is not energized.

Relay 227 includes a coil 23?, a compound armature or electric conducting bar 241 which is divided in its midregion to electrically insulate the two ends from each other, and three groups of contacts, the first of which includes contact points 242 and 243, the second of which includes contact points 244 and 246, and the third of which includes contacts 247 and 248. The armature 241 is biased, or resiliently loaded, for normal engagement of the contacts of the first two groups, i.e., contacts 242, 243, and 244, 246, when the coil 2319 is not energized. Contacts 247 and 248 are simultaneously contacted by one electrical conducting end of the armature 241 when the coil 239 is energized.

The open contact side of switch 117 is connected by wires to contacts 237 and 234 of relay 226. Contact 233 of relay 226 is connected by wires to contact 247 and contact 243 of relay 227. Contact 236 of relay 226 is connected to one end of the valve solenoid 211), the other end of the solenoid being connected to a return circuit of the power line.

The open contact side of switch 118 is connected by wires to contact 233 of relay 22d, and contact 244 of relay 227. Contact 246 of relay 227 is connected to one side of the coil 231 of relay 226, the other side of the coil being connected to the return circuit of the power line. Contact 242 of relay 227 is connected to one end of the solenoid 199, the opposite end of the solenoid being connected to the return circuit of the power lie.

The open contact side of switch 216 is connected by a wire to one side of the coil 239 of relay 227, the opposite side of said coil being connected to the return circuit of the power line. The contact 243 is connected to the incoming wire of coil 239.

It will be noted that the valve 269 includes a cylindrical slide valve 251 adapted in one position to admit pressure fluid from a supply pipe 252, to pipe 2593, and in another position to admit pressure fluid from pipe 252 to pipe 9 207. The slide valve is adapted so that in either position it will vent the non-pressurized side of the piston 205 by means of return pipes 253 or 254. The spring 228 is arranged to draw the slide valve 251 to the position shown, when the solenoid 210 is not energized.

Upon closure of a master switch 256 in the power circuit, the machine will be in readiness for an operating cycle, which will begin with the operator applying pressure to the lower end of the plunger assembly 90 to close the contact of switch 117. When this occurs current will fiow through switch 117 to contact 234, through armature 232, from contact 233 through the wire to contact 243, a portion or" the armature 241 to contact 242, and from the latter via wire to solenoid 109, through the solenoid and into the return circuit of the power line. Accordingly, the solenoid being so energized will cause upward movement of the rod 93 to bulge the rubber cylindrical element 104 and force the cup-shaped closure member 221 into engagement with the threads of the threaded opening 223 of a workpiece. Such upward movement of rod 93 will result in the closing of switch 118, whereupon current will flow through switch 118 to contact 244 of solenoid 227, through a portion of the armature 241 to contact 246 and then by wire to coil 231 of armature 226, and onward to the return circuit of the power line. Coil 231 upon being thus energized will draw armature 232 away from engagement with contacts 233, 234, and into engagement with contacts 236, 237, and 238. As a result, the circuit through solenoid 109 will be disrupted, and a circuit will be completed from the switch 117 through contact 237, armature 232, contact 236, and through Wires leading to the solenoid 210 and the return circuit of the power line. Solenoid 210 upon being energized, will shift the slide valve 251 so that pressure fluid will flow from supply pipe 252, to pipe 207, and the lower end of cylinder 206, to force the piston 205 upwardly therein. A holding circuit will be established through relay 221; when the coil 231 is energized, which circuit includes flow of current from switch 117 to contact 237, through armature 232 to the contact 23?, and through the wire to contact 244 of relay 227, through a portion of the armature 241, contact 246, and through the coil 231 to the return circuit of the power line.

Movement of the piston 205 upwardly will continue until the finger 213 engages the plunger 214 of the switch 216, to close the contact thereto. When this occurs, current will flow through switch 216, and through coil 239 of relay 227, and to the return circuit of the power line. The energization of coil 239 will draw the armature to break electrical connection between contacts 242, 243, and contacts 244, 246, and will make connection between contacts 247 and 2455. As a result, the holding circuit through relay 226 will be disrupted, and the armature 232 will move back into engagement with contacts 233 and 234. Simultaneously, a holding circuit Will be provided through relay 227 by current flowing from closed switch 117 through the wire leading to contact 234, armature 232, and contact 233, and then through the wire leading to contact 247 of relay 227, through a portion of the armature 246, contact 248, into Wire leading to the coil 239 and thence into the return circuit of the power line. Such condition will prevail until switch 117 is opened by action of the cam 113 at the time the plunger assembly 90 reaches the full extent of its downward movement. Upon opening of switch 117 the holding circuit through relay 227 will be disrupted and the armature 241 will move back into engagement with contacts 242, 243, and contacts 24-4, 246. It will be seen that the electrical circuit will thus be conditioned for initiation of another machine operating cycle.

From the foregoing it will be apparent that the method of the invention may be practised by manually operable means, or by automatically operable means to fulfill the objectives of the invention as set forth at the beginning of the specification.

The foregoing description has been given in detail without thought of limitation since the inventive principles involved are capable of assuming other physical embodiments without departing from the spirit of the invention and the scope of the appended claims.

What is claimed is:

1. A method for forming a protective closure for a threaded opening comprising the steps of placing a thin malleable sheet over an opening in a die block, forcing said sheet into said opening by means of a radially expandable rubber plunger of substantially uniform diameter to form a cup-shaped member having a side wall, and removing said plunger with said member thereon from said die block, inserting said plunger with said member still thereon into said threaded opening, and expanding said plunger to force said side wall outwardly so that it conforms to the threads of said threaded opening.

2. A method for forming a protective closure for a threaded opening comprising the steps of placing a metal foil over an opening formed in a die block, forcing the foil into the opening by means of a radially expandable rubber plunger of substantially uniform diameter to form a cup-shaped member having a side wall of uniform thickness, removing said plunger with said member thereon from said die block, inserting said plunger with said member still thereon into said threaded opening, expanding said plunger to force said side wall outwardly so that threads are formed throughout its thickness conforming to the threads of said threaded opening, and contracting and removing said plunger from said threaded opening so that said member remains in position within said threaded opening.

References (Iited in the file of this patent UNITED STATES PATENTS 210,784 King Dec. 10, 1878 1,792,897 De Lacy Feb. 17, 1931 1,853,944 Unke Apr. 12, 1932 1,934,292 Barker Nov. 7, 1933 2,131,978 Schwartz Oct. 4, 1938 2,143,480 Gunderman Jan. 10, 1939 2,158,044 Halter May 9, 1939 2,321,085 Hubbard June 8, 1943 2,417,202 Hull et al. Mar. 11, 1947 2,458,854 Hull et al Jan. 11, 1949 2,507,194 Chyba May 9, 1950 2,695,446 eyer Nov. 30, 1954 2,730,136 Phillips Jan. 10, 1956 2,748,463 Mueller June 5, 1956 2,789,721 Schoessow Apr. 23, 1957 2,847,757 Mock et al Aug. 19, 1958 2,954,495 Zeller Sept. 27, 1960 

1. A METHOD FOR FORMING A PROTECTIVE CLOSURE FOR A THREADED OPENING COMPRISING THE STEPS OF PLACING A THIN MALLEABLE SHEET OVER AN OPENING IN A DIE BLOCK, FORCING SAID SHEET INTO SAID OPENING BY MEANS OF A RADIALLY EXPANDABLE RUBBER PLUNGER OF SUBSTANTIALLY UNIFORM DIAMETER TO FORM A CUP-SHAPED MEMBER HAVING A SIDE WALL, AND REMOVING SAID PLUNGER WITH SAID MEMBER THEREON FROM SAID DIE BLOCK, INSERTING SAID PLUNGER WITH SAID MEMBER STILL THEREON INTO SAID THREADED OPENING, AND EXPANDING SAID PLUNGER TO FORCE SAID SIDE WALL OUTWARDLY SO THAT IT CONFORMS TO THE THREADS OF SAID THREADED OPENING. 